White Christmas Probabilities and Statistics

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DCZ001-MDZ003>007-009>011-013-014-016>018-501-502-VAZ025>031-
036>040-042-050>057-501>504-WVZ050>053-055-501>506-130645-
DISTRICT OF COLUMBIA-WASHINGTON-FREDERICK MD-CARROLL-
NORTHERN BALTIMORE-HARFORD-MONTGOMERY-HOWARD-SOUTHERN BALTIMORE-
PRINCE GEORGES-ANNE ARUNDEL-CHARLES-ST. MARYS-CALVERT-
EXTREME WESTERN ALLEGANY-CENTRAL AND EASTERN ALLEGANY-AUGUSTA-
ROCKINGHAM-SHENANDOAH-FREDERICK VA-PAGE-WARREN-CLARKE-NELSON-
ALBEMARLE-GREENE-MADISON-RAPPAHANNOCK-LOUDOUN-ORANGE-CULPEPER-
PRINCE WILLIAM/MANASSAS/MANASSAS PARK-FAIRFAX-
ARLINGTON/FALLS CHURCH/ALEXANDRIA-STAFFORD-SPOTSYLVANIA-
KING GEORGE-NORTHERN FAUQUIER-SOUTHERN FAUQUIER-WESTERN HIGHLAND-
EASTERN HIGHLAND-HAMPSHIRE-MORGAN-BERKELEY-JEFFERSON-HARDY-
WESTERN GRANT-EASTERN GRANT-WESTERN MINERAL-EASTERN MINERAL-
WESTERN PENDLETON-EASTERN PENDLETON-
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
139 PM EST WED DEC 12 2012
* * * * * * ** * * * *
* * WHITE CHRISTMAS STATISTICS * * *
* * * * * *
IT IS TIME AGAIN FOR THE CHRISTMAS STATISTICS FOR BALTIMORE AND
WASHINGTON...AS COMPILED BY THE NATIONAL WEATHER SERVICE'S
BALTIMORE/WASHINGTON FORECAST OFFICE.
WHAT ARE THE CHANCES FOR A WHITE CHRISTMAS? ...
WHAT IS TYPICAL CHRISTMAS WEATHER? ...
FIRST FOR WASHINGTON...THEN FOR BALTIMORE...
*** WASHINGTON DC ***
EXAMINATION OF CLIMATE RECORDS GOING BACK TO 1872 FOR CHRISTMASES IN
WASHINGTON DC SHOW A TYPICAL CHRISTMAS DAY IS PARTLY CLOUDY WITH A
FROSTY EARLY MORNING LOW OF 30 AND AN AFTERNOON HIGH OF 44. BUT THE
YEAR-TO-YEAR WEATHER CAN VARY CONSIDERABLY.
COLDEST CHRISTMASES...
THE COLDEST WAS 1983. THE LOW TEMPERATURE WAS 3 DEGREES ABOVE ZERO.
THAT DAY ALSO PRODUCED THE COLDEST HIGH TEMPERATURE FOR THE DAY...A
FRIGID 14 DEGREES THAT AFTERNOON. THE FIVE COLDEST LOW TEMPERATURES
WERE:
1983 - 3 DEGREES
1872 - 5 DEGREES
1989 - 11 DEGREES
1980 - 12 DEGREES
1906 - 13 DEGREES
WARMEST CHRISTMASES...
THE WARMEST CHRISTMAS DAY WAS A TOASTY 72 DEGREES IN 1964. THE 5
WARMEST CHRISTMASES:
1964 - 72 DEGREES
1982 - 70 DEGREES
1965 - 69 DEGREES
1932 - 68 DEGREES
1889 - 65 DEGREES
RECENT PAST CHRISTMAS DAY WEATHER:
LAST YEAR...HIGH PRESSURE SAW TO IT THAT WE HAD SEASONABLE TEMPERATURES
AND A FAIR AMOUNT OF SUN WITH JUST A FEW HIGH CLOUDS. REAGAN NATIONAL
AIRPORT...THE OFFICIAL MEASUREMENT LOCATION FOR WASHINGTON...RECORDED
AN EARLY MORNING LOW OF 34...RISING TO AN AFTERNOON HIGH OF 48 DEGREES.
2011 --> HI 48 LOW 34 MOSTLY SUNNY AND SEASONABLE
2010 --> HI 36 LOW 32 CLOUDY/MORNING FLURRIES
2009 --> HI 47 LOW 29 SNOWMELT/CLOUDY/MID AFTERNOON-NIGHT RAIN
2008 --> HI 58 LOW 32 PARTLY SUNNY HIGH OCCURRED AT MIDNIGHT
2007 --> HI 52 LOW 37 PARTLY SUNNY AND MILD
2006 --> HI 50 LOW 37 CLOUDY WITH AFTERNOON AND NIGHT RAIN
2005 --> HI 44 LOW 30 CLOUDY WITH AFTERNOON RAIN
2004 --> HI 33 LOW 24 SUNNY AND COLD
2003 --> HI 42 LOW 31 MOSTLY SUNNY AND BLUSTERY
2002 --> HI 39 LOW 33 RAIN WITH SOME SNOW/SLEET
2001 --> HI 41 LOW 28 MOSTLY SUNNY AND COOL
2000 --> HI 28 LOW 19 SUNNY BREEZY AND COLD
FOR SNOW LOVERS...
SNOW FALLING ON CHRISTMAS DAY IS A RARITY IN WASHINGTON. OF THE PAST
128 YEARS SINCE 1884 WHEN SNOWFALL HAS BEEN MEASURED IN WASHINGTON...
ONLY 10 TIMES HAS THERE BEEN MEASURABLE SNOW THAT ACTUALLY FELL ON
CHRISTMAS DAY. THAT AVERAGES TO ABOUT ONCE EVERY 12-13 YEARS...OR ABOUT
8 PERCENT.
THE 6 HIGHEST SNOWFALLS OCCURRING IN WASHINGTON ON CHRISTMAS DAY...
1... 1962 ... 5.4 INCHES
2... 1909 ... 4.5 INCHES
3... 1969 ... 4.3 INCHES
4... 1902 ... 1.0 INCHES
5... 1935 ... 0.6 INCHES
6... 1892 ... 0.5 INCHES
IF YOU INTERPRET A WHITE CHRISTMAS AS EITHER MEASURABLE SNOWFALL THAT
DAY OR HAVING SNOW ALREADY ON THE GROUND (A SNOW DEPTH OF AN INCH OR
MORE)...THE ODDS OF A WHITE CHRISTMAS ARE SLIGHTLY BETTER. SINCE
1888...NINETEEN TIMES MEASURABLE SNOW WAS ON THE GROUND ON CHRISTMAS
DAY THAT EITHER FELL THAT DAY...OR WAS STILL ON THE GROUND FROM AN
EARLIER SNOWFALL. THAT AVERAGES TO A WHITE CHRISTMAS ABOUT ONCE EVERY
6-7 YEARS...OR A 15 PERCENT CHANCE.
IN THE PAST 20 YEARS...THERE HAVE BEEN ONLY TWO CHRISTMASES THAT HAD
SNOWFALL...1993 AND 2002. BOTH YEARS FEATURED JUST A FRACTION OF AN
INCH. FURTHERMORE...THERE WERE ONLY TWO YEARS IN THE PAST 40 THAT HAD
AN INCH OR MORE OF SNOW ON THE GROUND ON CHRISTMAS. THEY WERE DURING
THE VERY COLD DECEMBER OF 1989...WHEN NEARLY 2 INCHES OF SNOW WAS ON
THE GROUND FROM PREVIOUS SNOWFALL THAT MONTH...AND MORE RECENTLY IN 2009
WHEN 7 INCHES WAS STILL ON THE GROUND FROM THE FIRST OF OUR MAJOR
SNOWSTORMS THAT RECORD SETTING WINTER. ALL 7 INCHES OF THAT SNOWPACK ON
CHRISTMAS 2009 MELTED BY THE NEXT MORNING.
OF NOTE...18 YEARS AGO...IN 1993 IN A SPAN LASTING LESS THAN 30
MINUTES IN THE EVENING...0.2 INCH SNOW FELL...WITH UPWARDS OF AN
INCH FALLING IN THE WESTERN SUBURBS. THAT QUICK BURST OF SNOW ON
CHRISTMAS NIGHT 1993 CAUSED SEVERE TRAVEL PROBLEMS. MUCH OF THE SNOW
MELTED ON CONTACT WITH PAVED SURFACES AS TEMPERATURES WERE JUST
ABOVE FREEZING AT THE TIME THE SNOW FELL. HOWEVER...AN ARCTIC COLD
FRONT SWEPT IN JUST AFTER THE SNOW ENDED. ANY WATER REMAINING ON
ROADS AND SIDEWALKS FROM MELTED SNOW QUICKLY FLASH FROZE INTO A THIN
LAYER OF ICE...WHICH CAUSED GRIDLOCK AND TREACHEROUS TRAVEL THAT NIGHT.
PRECIPITATION OF ANY SORT (RAIN INCLUDED) IS MUCH EASIER TO COME BY
OF COURSE. FIFTY-ONE CHRISTMASES HAVE HAD MEASURABLE PRECIPITATION.
THAT TRANSLATES TO ABOUT A 36 PERCENT PROBABILITY OF MEASURABLE
PRECIPITATION...OR ROUGHLY ONE IN EVERY THREE YEARS.
*** BALTIMORE MD ***
EXAMINATION OF WEATHER RECORDS GOING BACK TO 1872...SHOWS A TYPICAL
CHRISTMAS DAY IS PARTLY CLOUDY WITH A FROSTY EARLY MORNING LOW OF 26
AND AN AFTERNOON HIGH OF 43. BUT THE YEAR-TO-YEAR WEATHER CAN VARY
CONSIDERABLY.
COLDEST CHRISTMASES...
THE COLDEST...1983 WHEN THE TEMPERATURE HIT ZERO DEGREES. THAT DAY ALSO
PRODUCED THE COLDEST HIGH TEMPERATURE FOR THE DAY...A FRIGID 12 DEGREES
THAT AFTERNOON. THE FIVE COLDEST LOWS WERE:
1983 - 0 DEGREES
1980 - 7 DEGREES
1989 - 7 DEGREES
1960 - 12 DEGREES
1998 - 13 DEGREES
WARMEST CHRISTMASES...
THE WARMEST WAS A TOASTY 72 DEGREES IN 1964. THE 5 WARMEST CHRISTMASES:
1964 - 72 DEGREES
1982 - 70 DEGREES
1932 - 67 DEGREES
1893 - 67 DEGREES
1889 - 67 DEGREES
RECENT PAST CHRISTMAS DAY WEATHER:
LAST YEAR...HIGH PRESSURE SAW TO IT THAT WE HAD SEASONABLE TEMPERATURES
AND A FAIR AMOUNT OF SUN WITH JUST A FEW MAINLY HIGH CLOUDS. THURGOOD
MARSHALL BWI AIRPORT RECORDED AN EARLY MORNING LOW OF 24...RISING TO AN
AFTERNOON HIGH OF 48 DEGREES.
DURING THE AFTERNOON.
2011 --> HI 48 LOW 24 MOSTLY SUNNY AND SEASONABLE
2010 --> HI 34 LOW 29 CLOUDY/LIGHT SNOW IN THE MORNING
2009 --> HI 42 LOW 19 SNOWMELT/CLOUDY/LATE AFTERNOON-NIGHT RAIN
2008 --> HI 59 LOW 32 PARTLY SUNNY HIGH OCCURRED AT MIDNIGHT
2007 --> HI 50 LOW 30 PARTLY SUNNY AND MILD
2006 --> HI 50 LOW 30 CLOUDY WITH AFTERNOON AND NIGHT RAIN
2005 --> HI 42 LOW 24 CLOUDY WITH AFTERNOON RAIN
2004 --> HI 31 LOW 17 SUNNY AND COLD
2003 --> HI 41 LOW 28 MOSTLY SUNNY AND BLUSTERY
2002 --> HI 38 LOW 32 RAIN WITH SOME SNOW/SLEET
2001 --> HI 40 LOW 23 PARTLY SUNNY AND COOL
2000 --> HI 27 LOW 17 SUNNY BREEZY AND COLD
FOR SNOW LOVERS...
SNOW FALLING ON CHRISTMAS DAY IS A RARITY IN BALTIMORE. IT LAST
HAPPENED TEN YEARS AGO IN 2002 WHEN A GENERALLY RAINY CHRISTMAS
MORNING CHANGED TO SNOW DURING THE LATE MORNING. ENOUGH FELL TO YIELD
AN INCH OF SNOWFALL. HOWEVER...OF THE PAST 119 YEARS SINCE 1893 WHEN
SNOWFALL HAS BEEN MEASURED IN BALTIMORE MD...ONLY TWELVE TIMES HAVE
THERE BEEN MEASURABLE SNOW THAT FELL ON CHRISTMAS DAY. THAT AVERAGES TO
ABOUT ONCE EVERY 10 YEARS...OR ABOUT 10 PERCENT.
THE 6 HIGHEST SNOWFALLS OCCURRING IN BALTIMORE ON CHRISTMAS DAY...
1... 1909 ... 9.3 INCHES
2... 1969 ... 6.1 INCHES
3... 1902 ... 3.0 INCHES
4... 1962 ... 2.9 INCHES
5... 1935 ... 1.2 INCHES
6... 2002 ... 1.0 INCHES
IF YOU INTERPRET A WHITE CHRISTMAS AS EITHER MEASURABLE SNOWFALL OR
HAVING SNOW ALREADY ON THE GROUND (A SNOW DEPTH OF AN INCH OR MORE)...
THE ODDS OF A WHITE CHRISTMAS IMPROVE. SINCE 1893...THERE HAVE BEEN
TWENTY FOUR CHRISTMASES THAT MEASURABLE SNOW EITHER FELL THAT DAY...OR
WAS ON THE GROUND ALREADY FROM A PREVIOUS STORM. THAT AVERAGES TO A
WHITE CHRISTMAS ABOUT ONCE EVERY 5 YEARS...OR A 20 PERCENT CHANCE.
IN THE PAST 20 YEARS THERE HAVE BEEN ONLY TWO CHRISTMASES THAT HAD
MEASURABLE SNOW FALL THAT DAY...1993 AND 2002. BOTH YEARS FEATURED AN
INCH OR LESS. FURTHERMORE...THERE WAS ONLY THREE YEARS IN THE PAST 40
THAT HAD MORE THAN AN INCH OF SNOW ON THE GROUND ON CHRISTMAS. THE MOST
RECENT WAS IN 2009 WHEN 6 INCHES WAS STILL ON THE GROUND FROM THE FIRST
OF OUR MAJOR SNOWSTORMS THAT RECORD SETTING WINTER. ALL 6 INCHES OF
THAT SNOWPACK MELTED BY THE NEXT MORNING.
PRECIPITATION OF ANY SORT (RAIN INCLUDED) IS MUCH EASIER TO COME BY
OF COURSE. FORTY-NINE CHRISTMASES HAVE HAD MEASURABLE PRECIPITATION.
THAT TRANSLATES TO ABOUT 35 PERCENT PROBABILITY OF MEASURABLE
PRECIPITATION...OR ROUGHLY ONE THIRD.
HAPPY HOLIDAYS!!
$$
NWS BALTIMORE/WASHINGTON JK/CS/SZ